Activity Overview
In this activity, students construct isosceles and equilateral triangles. They discover that if two sides of a triangle are congruent, then the angles opposite them are congruent. They understand that an equilateral triangle is also equiangular.
Before the Activity
Install the Cabri™: Jr. App on the students' graphing calculators using one of these two methods:
TI-Connect™, a TI Connectivity Cable, and the Unit-to-Unit Link Cable
TI-Navigator™ "send to class" feature
See the attached PDF file for detailed instructions for this activity
Print pages 15 - 16 from the attached PDF file for your class
During the Activity
Distribute the pages to the class.
Follow the Activity procedures:
Construct an isosceles triangle
Measure and label segments and angles of the triangle
Identify the sides and angles that are congruent
Verify this relationship with different isosceles triangles
Observe that if two sides of a triangle are congruent, then the angles opposite them are congruent
Create an equilateral triangle using the Regular Polygon feature
Measure the angles
Observe that if all sides of a triangle are equal, then the triangle is equiangular
Alter the triangle and verify if the relationship holds true for all equilateral triangles
After the Activity
Review student results:
As a class, discuss questions that appeared to be more challenging
Re-teach concepts as necessary